In recent years, various techniques for preventing an automobile accident at a blind intersection or the like has been proposed, due to an increasing accident rate at night time on the ground that the accidents in day time are none at all desirable.
That is, Japanese patent document JP-A-2004-306894 discloses a driving support apparatus that controls a light beam of the headlamp at a stop sign of an intersection. More practically, the apparatus directs the light beam on a ground inside of the intersection so that other vehicles approaching the intersection can recognize that there is a vehicle stopping closely at the intersection. In this manner, the accidents at the blind intersection at night time is prevented.
However, the controlling the light beam toward the ground in the intersection is not always a sufficient measure for preventing the accidents, because a driver of the other approaching vehicle do not always detect the light beam reflected on the ground, or because getting priority right regarding which vehicle passes the intersection first is solely dependent on the agreement of implicit decisions of the drivers on respective vehicles.